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Templates

SSPs: Basis of template building

Attenuation by dust

The use of dust attenuation is optionnal in SPARTAN. To use it you must select during the configuration of template at least one dust extinction curve and give a list of color excess values, E(B-V). At the moment, SPARTAN includes four attenuation curves (see plot below):

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Note

If you are willing to use a different dust attenuation prescription it is possible. To do that you must go into the EXT subdirectory of the SPARTAN input and put your new curve in that directory. You must as well add it to the Dust_SPARTAN.txt list.

Extinction by the Intergalactic Medium (IGM)

At the moment SPARTAN includes two (actually three) different IGM prescription:

  • The prescription of Madau+95

  • The prescription of Meiksin+06

  • Both of the previous prescription can be enhanced by the models of Thomas+17

The two first prescription provide a single IGM extinction curve per redshift which corresponds to the mean transmission at the considered redshift (these are accessible via mean_meiksin and mean_madau) during the configuration of a fitting run. Nevertheless, this assumes that at a certain redshift, all the LOS are populated by equivalent gazeous clouds density with equivalent properties. In Thomas+17 we created additional empirical curves that allows one to give a little bit more freedom. At any redshift, this prescription provides 6 additional curves that represent +/- 0.5, 1.0 and 1.5 sigma from the average curve. Example of curves sets are given in the figure (from Thomas+17) below.

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This prescription are available for both Madau and Meiksin configuration and are accessible via free_madau and free_meiksin during the configuration.

In the output of SPARTAN, 3(+3) parameters are computed:

  • The Lyman alpha transmission, computed between 1070 and 1170 Ang

  • The Lyman beta transmission, computed between

  • The Lyman gamma transmission, computed between

These quantities are computed on the IGM template itself and as an average of the transmission in the given wavelength ranges. For each of these parameters, the Best fit and PDF estimation are given (so 3+3 parameters).